37 
and flower bearing toward the ends or throughout; spikelets 2} to 3 lines long, ovate, 
acute; the empty glumes silky-villous; lower glume 7-nerved, two-thirds as long 
as the 15-nerved second glume ; third glume rather shorter, 11- to 13-nerved ; perfect 
flower oblong, glabrous, except on the margins, these long-ciliate.—In sand, south- 
ern California to Arizona. 
§ 10. Ecutnocu1oa Benth. 
65. P. colonum Linn. (P. Walteri Ell: Chapm. Fl. 8. 8. p. 577.) Culms 1 to 
2 feet high, erect or decumbent at the base; leaves flat, glabrous; panicle 2 to 4 
inches long, of several simple one-sided, distant, usually erect branches or sessile 
spikes, one-half to three-fourths inch long. Spikelets about 1 line long, ovoid, densely 
crowded in about 4 rows; outer glumes coarsely pubescent, or rarely glabrous, the first 
rarely half as long as the second and third, these nearly equal, often ending in 
short points, but not awned.—Introduced in the South, very common from Texas to 
California. 
66. P. Crus-galli Linn. (Gray’s Manual, 6th ed.,’p. 633.) Usually annual, culms 
coarse, decumbent, usually branching below, 2 to 4 feet high; leaves long, rough ; 
sheaths rough, hispid or smooth; panicle dense, of numerous simple sessile spikes 
1 to 2 inches long; spikelets crowded. and clustered, outer glumes strongly hispid, 
acute or sometimes with long hispid awns. Introduced and very common. In the 
South appearing to be native. Very variable in size and appearance. 
Var. HIRSUTUM, Torr, —Sheaths hirsute-pubescent or smooth; glumes long-awned. 
Var. MUTICUM, glumes without awns, 
§ 11. HymeNnaAcuNE Benth, 
67, P. gibbum Ell. (Chapm. Fl. S. States, p. 573.) Culms branched, decum- 
bent; ¥ to 3 feet high; leaves linear-lanceolate, acuminate to a long point, 6 to 
12 inches long, one-half to three-fourths inch wide; panicle 5 to 6 inches long, 
confined ; the branches appressed, 1 to 2 inches long; spikelets loosely crowded on 
pedicels about their own length, about 14 lines long, oblong, obtuse; the lower 
glume 5-nerved one-fourth as long as the second, the latter strongly 11-nerved, 
gibbous at the base; sterile flower with 3 stamens; fertile flower smooth, half as 
long as the spikelet.—Swamps South Carolina to Florida and Mississippi. 
OPLISMENUS Beauv. 
Spikelets in small, sessile, distant clusters of the simple panicle, the 
spikelets one-sided in the clusters, the lower and the second empty 
glumes always (and the third frequently) awned, the lower long-awned. 
1, O, setarius R, & 8. (Panicum hirtellum Linn: Chapm, Fl, 8. States,577.) Culms 
weak, decumbent and rooting below, 1 to 2 feet long; leaves ovate-lanceolate, 1 
to 14 inches long; panicle racemose, 3 to 4 inches long, consisting of 5 to 9 small 
sessile clusters of spikelets, each of 3 to 5; lower empty glume with an awn 3 to 4 
times as long as the spikelet, second a little shorter, the third less than a line 
long.—F lorida to Texas, coastwise. 
SETARIA Beany. 
Spikelets in a cylindrical spike-like or sometimes interrupted panicle. 
Below the articulation of the spikelets are several, usually many, bris- 
tles, which are supposed to be abortive branchlets and persistent after 
the fall of the spikelets. The spikelets contain one terminal fertile 
flower (its glume and palet indurated and striate), and usually a lower 
